Method of manufacturing photomask

ABSTRACT

A photomask includes a transparent substrate, a mask pattern formed on the substrate, and a protective layer pattern covering side walls of the mask pattern, wherein a top of the protective layer pattern is exposed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application based on pending application Ser. No.14/217,976 filed Mar. 18, 2014, the entire contents of which is herebyincorporated by reference.

Korean Patent Application No. 10-2013-0077847, filed on Jul. 3, 2013, inthe Korean Intellectual Property Office, and entitled: “Photomask AndMethod Of Manufacturing The Same,” is incorporated by reference hereinin its entirety.

BACKGROUND

Embodiments relate to a photomask and a method of manufacturing thesame.

SUMMARY

Embodiments are directed to a photomask including a transparentsubstrate, a mask pattern formed on the substrate, and a protectivelayer pattern covering side walls of the mask pattern. A top of theprotective layer pattern is exposed.

The top of the protective layer pattern and a top of the mask patternmay be positioned on a same plane.

The protective layer pattern may include a first area and a second area.The first area may be closer to the transparent substrate than thesecond area. A width of the first area may be larger than a width ofsecond area, the width of the first area and the width of the secondarea being measured in a direction parallel to the transparent substrateand perpendicular to a side surface of the mask pattern.

The mask pattern may include a third area and a fourth area. The firstarea may be on side walls of the third area and the second area is onside walls of the fourth area. A sum of widths of the first and thirdareas may be the same as a sum of widths of the second and fourth areas.

The protective layer pattern may include a first surface contacting themask pattern and a second surface exposed to the outside. The secondsurface is substantially vertical to the transparent substrate.

The mask pattern may include a first film including a first material anda second film including a second material different from the firstmaterial.

The mask pattern may include a plurality of films formed by alternatelylaminating the first film and the second film.

The first material may include at least one of Mo and Ru. The secondmaterial may include Si.

An etching rate of the protective layer pattern to H₂SO₄ and/or NH₄OHmay be lower than that of the mask pattern.

The mask pattern may include Mo. The protective layer pattern mayinclude at least one of Si, Cr, Ta, Zr, silicon oxide (SiO_(x)), siliconnitride (SiN_(x)), chromium oxide (CrO_(x)), chromium nitride (CrN_(x)),zirconium oxide (ZrO_(x)), tantalum oxide (TaO_(x)), and tantalumnitride (TaN_(x)).

Embodiments are also directed to a method of manufacturing a photomaskincluding forming a mask pattern on a transparent substrate, conformallyforming a protective layer on the top of the transparent substrate, theside wall of the mask pattern, and the top of the mask pattern, andforming a protective layer pattern on the side wall of the mask patternby patterning the protective layer, wherein the top of the protectivelayer pattern is exposed.

The patterning of the protective layer may include exposing the top ofthe mask pattern and the top of the transparent substrate.

The patterning of the protective layer may include patterning theprotective layer by an anisotropic etching process.

An etching rate of the protective layer pattern to H₂SO₄ and/or NH₄OHmay be lower than that of the mask pattern.

The forming of the protective layer may include forming the protectivelayer through an atomic layer deposition (ALD) process.

Embodiments are also directed to a photomask including a transparentsubstrate, a mask pattern formed on the substrate, the mask patternincluding sidewalls, and a protective layer pattern covering the sidewalls of the mask pattern, a top of the protective layer pattern beingexposed, the protective layer pattern being formed by depositing aprotective layer on the mask pattern through an atomic layer deposition(ALD) process and patterning the protective layer.

The top of the protective layer pattern and a top of the mask patternmay be on a same plane.

The mask pattern may include Mo. The protective layer pattern mayinclude at least one of Si, Cr, Ta, Zr, silicon oxide (SiO_(x)), siliconnitride (SiN_(x)), chromium oxide (CrO_(x)), chromium nitride (CrN_(x)),zirconium oxide (ZrO_(x)), tantalum oxide (TaO_(x)), and tantalumnitride (TaN_(x)).

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail exemplary embodiments with reference to the attached drawingsin which:

FIG. 1 illustrates a cross-sectional view of a photomask according to anembodiment.

FIG. 2 illustrates a cross-sectional view of a photomask according toanother embodiment.

FIG. 3 illustrates a cross-sectional view of a photomask according toanother embodiment.

FIG. 4 illustrates a cross-sectional view of a photomask according toanother embodiment.

FIG. 5 illustrates a cross-sectional view of a photomask according toanother embodiment.

FIG. 6 illustrates a flowchart of a method of manufacturing thephotomask according to an embodiment.

FIGS. 7 through 9 illustrate intermediate-stage diagrams of stages ofthe method disclosed FIG. 6.

FIGS. 10 and 11 illustrate intermediate-stage diagrams of the method ofmanufacturing the photomask according to another embodiment.

DETAILED DESCRIPTION

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey exemplary implementations to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may beexaggerated for clarity of illustration. It will also be understood thatwhen a layer or element is referred to as being “on” another layer orsubstrate, it can be directly on the other layer or substrate, orintervening layers may also be present. Like reference numerals refer tolike elements throughout.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the inventiveconcept. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise.

It is to be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer, or section fromanother region, layer, or section. Thus, a first element, component,region, layer, or section discussed below could be termed a secondelement, component, region, layer, or section without departing from theteachings.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper”, and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures.

Embodiments are described herein with reference to cross-sectionillustrations that are schematic illustrations of idealized embodiments(and intermediate structures). As such, variations from the shapes ofthe illustrations as a result, for example, of manufacturing techniquesand/or tolerances, are to be expected.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which the present inventive conceptbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand this specification and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

A photomask according to an embodiment will be described with referenceto FIG. 1.

FIG. 1 illustrates a cross-sectional view of a photomask according to anembodiment.

Referring to FIG. 1, a photomask 1 according to this embodiment includesa transparent substrate 10, mask patterns 20 a and 20 b, and protectivelayer patterns 30 a, 30 b, 30 c, and 30 d.

The transparent substrate 10 may include a material that transmitsexposed light and may include, for example, quartz or glass.

The mask patterns 20 a and 20 b are formed on the transparent substrate10. Two mask patterns 20 a and 2 b are illustrated in the figure. Inother implementations, when viewed in the cross-sectional view, only onemask pattern may be formed on the transparent substrate 10 or three ormore mask patterns may be formed. The tops of the mask patterns 20 a and20 b may be exposed.

The mask patterns 20 a and 20 b may be formed according to a layout of acircuit pattern to which the mask patterns 20 a and 20 b are to betransferred. The mask patterns 20 a and 20 b may use a material thatdoes not substantially transmit the exposed light and may include, forexample, a metallic material such as Mo, or the like and mayadditionally include Si, O, or N. A phrase “the mask patterns 20 a and20 b do not substantially transmit the exposed light” includes a case inwhich some exposed light is transmitted in addition to a case in whichthe exposed light is fully is blocked, as long as the layout of thecircuit pattern to be transferred may be formed.

The protective layer patterns 30 a, 30 b, 30 c, and 30 d may be formedon both side walls of the mask patterns 20 a and 20 b. A firstprotective layer pattern 30 a may be formed on one side wall of thefirst protective layer pattern 20 a, a second protective layer pattern30 b may be formed on the other side wall, a third protective layerpattern 30 c may be formed on one side wall of the second protectivelayer pattern 20 b, and a fourth protective layer pattern 30 d may beformed on the other side wall.

The protective layer patterns 30 a, 30 b, 30 c, and 30 d may fully coverboth side walls of the mask patterns 20 a and 20 b. Therefore, both sidewalls of the mask patterns 20 a and 20 b are not exposed.

The tops of the first and second protective layer patterns 30 a and 30 bmay be positioned on the same plane as the top of the first mask pattern20 a, and the third and fourth protective layer patterns 30 c and 30 dmay be positioned on the same plane as the second mask pattern 20 b. Theprotective layer patterns 30 a, 30 b, 30 c, and 30 d may have the sameheight as the mask patterns 20 a and 20 b. The tops of the protectivelayer patterns 30 a, 30 b, 30 c, and 30 d may be exposed.

The protective layer patterns 30 a, 30 b, 30 c, and 30 d may serve toprevent a decrease in line width of a light blocking film pattern in areproduction process of the photomask. The reproduction process of thephotomask includes a re-pellicle process of removing a pellicle thatprotects the photomask and attaching the pellicle again. An adhesivecomponent to attach the pellicle may be removed in order to remove thepellicle. To this end, a strip solution including solutions such assulfuric acid (H₂SO₄), ammonium hydroxide (NH₄OH), and the like may beused. If the side walls of the mask patterns 20 a and 20 b are exposed,the side walls of the mask patterns 20 a and 20 b could be etched by thestrip solution, and as a result, the line width could be decreased andtotal uniformity of the photomask patterns could be degraded.

In particular, as the degree of integration of a semiconductor deviceincreases, the likelihood that the quality and reliability of thesemiconductor device may be degraded increases even when a change in theline width of the photomask pattern is minute. When the protective layerpatterns 30 a, 30 b, 30 c, and 30 d are formed, the mask patterns 20 aand 20 b may be protected from being etched.

The protective layer patterns 30 a, 30 b, 30 c, and 30 d may be made ofa stable material that is not etched by a strip solution includingsulfuric acid (H₂SO₄), ammonium hydroxide (NH₄OH), or the like. Anetching rate of the protective layer patterns 30 a, 30 b, 30 c, and 30 dto the strip solution should be lower than an etching rate of the maskpatterns 20 a and 20 b to the strip solution in order to protect themask patterns 20 a and 20 b. Therefore, the protective layer patterns 30a, 30 b, 30 c, and 30 d may include a material different from a materialincluded in the mask patterns 20 a and 20 b. The protective layerpatterns 30 a, 30 b, 30 c, and 30 d may include, for example, at leastone of Si, Cr, Ta, Zr, silicon oxide (SiO_(x)), silicon nitride(SiN_(x)), chromium oxide (CrO_(x)), chromium nitride (CrN_(x)),zirconium oxide (ZrO_(x)), tantalum oxide (TaO_(x)), tantalum nitride(TaN_(s)), and the like.

A difference in etching rate between the mask patterns 20 a and 20 b andthe protective layer patterns 30 a, 30 b, 30 c, and 30 d may bedetermined by experimentation. When the materials react with first andsecond solutions, the thickness of a material that remains with time maybe measured. As the first and second solutions used in the experiment,solutions used as the strip solution may be used. In the experimentreported in Table 1, below, the first solution included H₂SO₄ and H₂O₂and the second solution included NH₄OH, H₂O₂, and H₂O. The experimentalresult is described in [Table 1].

TABLE 1 Thickness (nm) First solution Second solution Material 0 min 30min 60 min 0 min 30 min 60 min Mo 181 0 0 181 0 0 Si 80 81 80 80 80 78Cr 87 87 85 87 87 85 Ta 138 138 137 138 136 137 Zr 128 126 124 125 124124 SiOx 173 171 170 172 171 171 SiNx 136 133 133 136 134 133 CrOx 81 8179 79 79 78 CrNx 118 117 115 118 116 116 ZrOx 42 38 32 42 38 32 ZrNx 790 0 81 79 79 TaOx 70 70 70 70 70 70 TaNx 72 71 70 71 71 71

It can be seen that an etching amount of Mo by the first and secondsolutions is large. However, it can also be seen that other materialswere not etched by the first and second solutions or that the etchingamounts of other materials were small compared to the etching amount ofMo. It can also be seen that zirconium nitride (ZrNx) was barely etchedby the second solution, but was etched by the first solution. Therefore,when the first solution is used as the strip solution in thereproduction process of the photomask, zirconium nitride should not beused as the protective layer patterns 30 a, 30 b, 30 c, and 30 d.

A first width L1 of the first mask pattern 20 a and the first protectivelayer pattern 30 a and the second protective layer pattern 30 b formedon both side walls of the first mask pattern 20 a may be varieddepending on the layout of the circuit pattern. When the photomask 1 isused, a semiconductor device having a line width (CD) of L1 and L2 maybe formed. The first width L1 may be different from or the same as thesecond width L2 of the third protective layer pattern 30 c and thefourth protective layer pattern 30 d formed on both side walls of thesecond mask pattern 20 b and the first mask pattern 20 a.

A photomask according to another embodiment will be described withreference to FIG. 2. A description of a content duplicated withdescribed above is not repeated, and a difference will be primarilydescribed.

FIG. 2 illustrates a cross-sectional view of a photomask according tothis other embodiment.

Referring to FIG. 2, in a photomask 2 according to this embodiment, themask patterns 23 a and 23 b may be formed with two layers, unlike thephotomask 1 according to the first embodiment. The first mask pattern 23a may include a first anti-reflection film pattern 24 a and a firstlight blocking film pattern 24 b, and the second mask pattern 23 b mayinclude a second anti-reflection film pattern 24 c and a second lightblocking film pattern 24 d.

The light blocking film patterns 24 b and 24 d may be formed on thetransparent substrate 10. The light blocking film patterns 24 b and 24d, and the light blocking film pattern formed of the light blocking filmpatterns 24 b and 24 d may include a material that does notsubstantially transmit the exposed light. For example, the lightblocking film pattern 115 may include a metallic material such aschromium (Cr).

The anti-reflection film patterns 24 a and 24 c may be formed on thelight blocking film patterns 24 b and 24 d. The anti-reflection filmpatterns 24 a and 24 c may be formed to absorb reflected light that maybe reflected from a wafer during exposure. The anti-reflection filmpatterns 24 a and 24 c may include a metal nitride or metal oxide. Forexample, the anti-reflection film patterns 24 a and 24 c may include atleast one of chromium oxide, chromium nitride, molybdenum (Mo),molybdenum oxide, molybdenum nitride, and molybdenum oxynitride. Theanti-reflection film patterns 24 a and 24 c and the light blocking filmpatterns 24 b and 24 d may include different materials.

The protective layer patterns 30 a, 30 b, 30 c, and 30 d may be formedto cover both side walls of the anti-reflection film patterns 24 a and24 c and the light blocking film patterns 24 b and 24 d. The tops of theprotective layer patterns 30 a, 30 b, 30 c, and 30 d may be exposed, andboth side walls of the anti-reflection film patterns 24 a and 24 c andthe light blocking film patterns 24 b and 24 d may not be exposed by theprotective layer patterns 30 a, 30 b, 30 c, and 30 d.

A photomask according to another embodiment will be described withreference to FIG. 3. A description of a content duplicated with thecontent described above is not repeated, and a difference will beprimarily described.

FIG. 3 illustrates a cross-sectional view of a photomask according tothis other embodiment.

Referring to FIG. 3, in a photomask 3 according to this embodiment, themask patterns 25 a and 25 b may include a plurality of films unlike thephotomask 1 according to the embodiment illustrated in FIG. 1. The maskpatterns 25 a and 25 b may include first films 26 b and 26 d, secondfilms 26 a and 26 c, a capping film pattern 28, an absorption filmpattern 29, or the like.

The mask patterns 25 a and 25 b may include the first films 26 b and 26d including a first material and the second films 26 a and 26 cincluding a second material. The first material and the second materialmay be different from each other. For example, the first material may beMo or Ru and the second material may be Si.

The first films 26 b and 26 d and the second films 26 a and 26 c may bealternately laminated. For example, the first films 26 b and 26 d andthe second films 26 a and 26 c may be laminated with approximately 30 to60 layers.

After the first films 26 b and 26 d and the second films 26 a and 26 care laminated, the capping film pattern 28 and the absorption filmpattern 29 may be sequentially formed. The capping film pattern 28 mayserve to protect the first films 26 b and 26 d and the second films 26 aand 26 c and to help the absorption film pattern 29 to be easily bonded.The capping film pattern 28 may be made of, for example, silicon oxide,aluminum oxide, chromium oxide, or chromium nitride.

The absorption film pattern 29 may be formed on the capping film pattern28 and may serve to prevent the exposed light from being reflected. Theabsorption film pattern 29 may be made of, for example, tantalumnitride, or the like.

A photomask according to another embodiment will be described withreference to FIG. 4. A description of content duplicative with thecontent described above is not repeated, and a difference will beprimarily described.

FIG. 4 illustrates a cross-sectional view of a photomask according tothis other embodiment.

Referring to FIG. 4, in a photomask 4 according to this embodiment, theshapes of the mask patterns 21 a and 21 b and the protective layerpatterns 31 a, 31 b, 31 c, and 31 d may be different from those of thephotomask 1 according to the embodiment illustrated in FIG. 1. Indetail, the first mask pattern 21 a may include a third area 40 and afourth area 41. The third area 40 may be disposed closer to thetransparent substrate 10 than the fourth area 41. A width W3 of thethird area 41 may be different from a width W4 of the fourth area 41.The width W3 of the third area 41 may be smaller than the width W4 ofthe fourth area 41 in FIG. 4.

The mask patterns 21 and 21 b may include Mo, Si, O, N, or the like asdescribed above. However, when the mask patterns 21 a and 21 b areformed, contents of the materials may be different from each other inthe third area 40 and the fourth area 41. A difference in an etchingamount may occur while forming the mask patterns 21 a and 21 b due tothe difference in content of the material. As a result, the width W3 ofthe third area 40 may be smaller than the width W4 of the fourth area41.

The protective layer patterns 31 a, 31 b, 31 c, and 31 d may be formedon both side walls of the mask patterns 21 a and 21 b. In detail, afirst protective layer pattern 31 a may be formed on one side wall ofthe first mask pattern 21 a and a second protective layer pattern 31 bmay be formed on the other side wall of the first mask pattern 21 a. Thefirst and second protective layer patterns 31 a and 31 b may includefirst areas 33 a and 34 a and second areas 33 b and 34 b, respectively.The first areas 33 a and 34 a may be disposed closer to the transparentsubstrate 10 than the second areas 33 b and 34 b. Widths W1 and W5 ofthe first areas 33 a and 34 a may be larger than widths W2 and W6 of thesecond areas 33 b and 34 b. The reason is that a width W3 of the thirdarea 40 is smaller than a width W4 of the fourth area 41, and as aresult, a part where the third area 40 is not disposed is formed belowthe fourth area 41 and the part which the third area 40 is not disposedis filled with the first areas 33 a and 34 a.

Even though upper and lower widths of the first and second protectivelayer patterns 31 a and 31 b and the first mask pattern 21 a aredifferent from each other, overall widths thereof may be the same aseach other. In detail, the sum of the widths W1 and W5 of the firstareas 33 a and 34 a and the width W3 of the third area 21 a may be thesame as the sum of the widths W2 and W6 of the second areas 33 b and 34b and the width W4 of the fourth area 41. Therefore, an overall width L3of the first mask pattern 21 a and the first and second protective layerpatterns 31 a and 31 b formed on both side walls of the first maskpattern 21 a may be continuously uniform. An overall width L4 of thesecond mask pattern 21 b and the third and fourth protective layerpatterns 31 c and 31 d formed on both side walls of the second maskpattern 21 b may also continuously uniform. Herein, L3 may be the sameas L1 of FIG. 1, and L4 may be the same as L2 of FIG. 1.

The shape of the mask patterns 21 a and 21 b and the protective layerpatterns 31 a, 31 b, 31 c, and 31 d illustrated in FIG. 4 may beexpressed differently, as explained below. The first and secondprotective layer patterns 31 a and 31 b may include a first surfacecontacting the first mask pattern 21 a and a second surface exposed tothe outside. The shape of the first surface may depend on the shape ofthe first mask pattern 21 a, but the second surface may be substantiallyvertical to the transparent substrate 10. Herein, the statement that“the second surface is substantially vertical to the transparentsubstrate 10” may include implementations in which an angle between thesecond surface and the transparent substrate is in a range of betweenabout 80° and about 100°, in addition to an implementation where theangle is 90°.

A photomask according to another embodiment will be described withreference to FIG. 5. A description of a content that is duplicative ofthe content described above is not repeated, and a difference will beprimarily described.

FIG. 5 illustrates a cross-sectional view of a photomask according tothis other embodiment.

Referring to FIG. 5, a photomask 5 according to this embodiment isdifferent from the photomask 2 according to the second embodiment withregard to the shapes of mask patterns 22 a and 22 b.

The mask patterns 22 a and 22 b may include a light blocking filmpatterns 42 a and 42 b and anti-reflection film patterns 43 a and 43 b.The light blocking film patterns 24 b and 24 d and the anti-reflectionfilm patterns 24 a and 24 c are shown to have the same width in FIG. 2.However, in the embodiment illustrated in FIG. 5, the light blockingfilm patterns 24 b and 24 d and the anti-reflection film patterns 24 aand 24 c have different widths. Widths of the light blocking filmpatterns 42 a and 42 b may be smaller than widths of the anti-reflectionfilm patterns 43 a and 43 b. Materials included in the light blockingfilm patterns 42 a and 42 b and the anti-reflection film patterns 43 aand 43 b may be different from each other, and the widths of bothpatterns may be different from each other.

The widths of the light blocking film patterns 42 a and 42 b and thewidths of the anti-reflection film patterns 43 a and 43 b may bedifferent from each other. Accordingly, the shapes of protective layerpatterns 32 a, 32 b, 32 c, and 32 d formed on both side walls of thelight blocking film patterns 42 a and 42 b and the anti-reflection filmpatterns 43 a and 43 b may also be different from those of the photomask2 in FIG. 2. First and second protective layer patterns 32 a and 32 bmay include fifth areas 35 a and 36 a and sixth areas 35 b and 36 b. Thefifth areas 35 a and 36 a may be closer to the transparent substrate 10than the sixth areas 35 b and 36 b. The fifth areas 35 a and 36 a mayfill a part where the first light blocking film pattern 42 a is notdisposed below the first ant-reflection film pattern 43 a. Therefore,widths W7 and W9 of the fifth areas 35 a and 36 a may be larger thanwidths W8 and W10 of the sixth areas 35 b and 36 b.

A value acquired by adding the widths W8 and W10 of the sixth areas 35 band 36 b and the width of the first anti-reflection film pattern 43 amay be the same as a value acquired by adding the widths W7 and W9 ofthe fifth areas 35 a and 36 a and the width of the first light blockingfilm pattern 42 a. Therefore, the first and second protective layerpatterns 32 a and 32 b, the first anti-reflection film pattern 43 a, andthe first light blocking film pattern 42 a may have a rectangular shapeoverall. The side walls of the first and second protective layerpatterns 32 a and 32 b that do not contact the first anti-reflectionfilm pattern 43 a and the first light blocking film pattern 42 a and areexposed to the outside may be substantially vertical to the transparentsubstrate 10.

A method of manufacturing the photomask according to an embodiment willbe described with reference to FIG. 1 and FIGS. 6 through 9. Adescription of content duplicative of the content described above willnot be repeated.

FIG. 6 illustrates a flowchart of a method of manufacturing thephotomask according to the first embodiment and FIGS. 7 through 9illustrate intermediate-stage diagrams of stages of the method of FIG.6.

First, the mask patterns 20 a and 20 b may be formed on the transparentsubstrate 10 (S100). Referring to FIG. 7, a mask 20 may be formed on thetransparent substrate 10. A quartz or glass substrate may be used as thetransparent substrate 10, as described above. The mask 20 may be formedby using, for example, physical vapor deposition (PVD), sputtering, oratomic layer deposition (ALD). The mask 20 may include, for example, ametallic material such as Mo, or the like and may additionally includeSi, O, or N. In other implementations, the mask 20 may include Cr,chromium oxide, or the like.

Referring to FIG. 8, the mask patterns 20 a and 20 b may be formed bypatterning the mask 20.

In order to form the mask patterns 20 a and 20 b, for example, aphotoresist pattern (not illustrated) may be formed on the mask 20 andthe mask 20 may be partially removed by using the photoresist pattern asan etching mask. A dry etching or wet etching process may be performedin order to partially remove the mask 20.

Referring to FIG. 9, a protective layer 30 may be formed on the sidewalls of the mask patterns 20 a and 20 b (S200). The protective layer 30may be conformally formed on the top of the transparent substrate 10,the side walls of the mask pattern 20 a and 20 b, and the tops of themask patterns 20 a and 20 b. The protective layer 30 may be formedthrough the ALD process. When the protective layer 30 is formed by theALD, the protective layer 30 may be formed of a material different fromthe mask patterns 20 a and 20 b, and the protective layer 30 may beeasily formed to a desired thickness.

Subsequently, the protective layer patterns 30 a, 30 b, 30 c, and 30 dmay be formed on the side walls of the mask patterns 20 a and 20 b likethe photomask 1 of FIG. 1 by patterning the protective layer 30 (S300).The protective layer 30 formed on the tops of the mask patterns 20 a and20 b and the top of the transparent substrate 10 may be removed so thatthe protective layer patterns 30 a, 30 b, 30 c, and 30 d are formed ononly the side walls of the mask patterns 20 a and 20 b. The protectivelayer patterns 30 a, 30 b, 30 c, and 30 d may fully cover the side wallsof the mask patterns 20 a and 20 b such that the side walls of the maskpatterns 20 a and 20 b are not exposed. The tops of the protective layerpatterns 30 a, 30 b, 30 c, and 30 d may be exposed.

An anisotropic etching process may be performed in order to pattern theprotective layer 30. For example, the patterning may be performedthrough the dry etching process.

The side walls of the mask patterns 20 a and 20 b could be oxidized ornitrified in order to form the protective layer patterns 30 a, 30 b, 30c, and 30 d. However, in such a case there is a risk that the protectivelayer patterns 30 a, 30 b, 30 c, and 30 d may not be formed accuratelywith a desired thickness through oxidization or nitrification.

The protective layer patterns 30 a, 30 b, 30 c, and 30 d may be formedto prevent the side walls of the mask patterns 20 a and 20 b from beingetched during the photomask reproduction process. It is desirable thatthe protective layer patterns 30 a, 30 b, 30 c, and 30 d not be etchedby the strip solution used during the reproduction process. Accordingly,the etching rate of the protective layer patterns 30 a, 30 b, 30 c, and30 d may be lower than the etching rate of the mask patterns 20 a and 20b with respect to H₂SO₄ and/or NH₄OH used for the strip solution. Thematerial included in the protective layer patterns 30 a, 30 b, 30 c, and30 d has been described above. Therefore, a description thereof will notbe repeated.

A method of manufacturing the photomask according to another embodimentwill be described with reference to FIGS. 4, 7, 10, and 11. Adescription of content that is duplicative of the content describedabove will not be repeated.

FIGS. 10 and 11 illustrate intermediate-stage diagrams of stages of themethod of manufacturing the photomask according to this embodiment.

In the method of manufacturing the photomask according to thisembodiment, the mask 20 is formed on the transparent substrate 10 asillustrated in FIG. 7. In addition, the mask patterns 21 a and 21 b areformed by patterning the mask 20 as illustrated in FIG. 10. However, themethod is different from the method of manufacturing the photomaskaccording to the previous embodiment with respect to the shapes of themask patterns 21 a and 21 b. In the method of manufacturing thephotomask according to this embodiment, the lower parts of the maskpatterns 21 a and 21 b may be more etched than the upper parts at thetime of patterning the mask 20. An etching amount of the lower parts ofthe mask pattern 21 a and 21 b may be greater than an etching amount ofthe upper parts. Accordingly, lower widths of the mask patterns 21 a and21 b may be smaller than upper widths of the mask patterns 21 a and 21b. Such a difference may be generated because the content of thematerials included in the upper parts and the lower parts in the maskpatterns 21 a and 21 b may be different from each other. The etchingamounts may be different from each other due to the difference in thematerial content.

Subsequently, a protective layer 31 may be conformally on thetransparent substrate 10, the side walls of the mask patterns 21 a and21 b, and the tops of the mask patterns 21 a and 21 b as illustrated inFIG. 11. The protective layer 31 may be formed through an ALD processinstead of through oxidation or nitrification. Therefore, the protectivelayer 31 may be formed accurately with a desired thickness.

Subsequently, the protective layer 31 formed on the side walls of themask patterns 21 a and 21 b may remain, and the protective layer 31 onthe remaining parts may be removed through anisotropic etching, forexample, through a dry etching process, to form the protective layerpatterns 31 a, 31 b, 31 c, and 31 d of FIG. 4. The tops of the maskpatterns 21 a and 21 b and the top of the transparent substrate 10 maybe partially exposed by the anisotropic etching. The photomask 4illustrated in FIG. 4 may be obtained by the method of manufacturing thephotomask according to this embodiment. Since the shape of the photomask4 has been described above in detail, a description thereof will not berepeated.

By way of summation and review, a photomask used in an exposure processfor manufacturing a semiconductor device may be repeatedly reusedthrough a reproduction process. The reproduction process includes are-pellicle process of removing a pellicle used to protect the photomaskand attaching the pellicle again.

However, a pattern of the photomask may be damaged or a change in linewidth may be caused due to a solution used to remove the pellicle. Inparticular, as the degree of integration of a semiconductor devicepattern has rapidly increased in recent years, a minute change of thepattern of the photomask may significantly degrade the quality andreliability of the semiconductor device.

Embodiments may provide a photomask having improved product reliabilityand a method of manufacturing the photomask having improved productreliability.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

1.-10. (canceled)
 11. A method of manufacturing a photomask, the methodcomprising: forming a mask pattern on a transparent substrate;conformally forming a protective layer on a top of the transparentsubstrate, a side wall of the mask pattern, and a top of the maskpattern; and forming a protective layer pattern on the side wall of themask pattern by patterning the protective layer, wherein the top of theprotective layer pattern is exposed.
 12. The method as claimed in claim11, wherein the patterning of the protective layer includes exposing thetop of the mask pattern and the top of the transparent substrate. 13.The method as claimed in claim 12, wherein the patterning of theprotective layer includes patterning the protective layer by ananisotropic etching process.
 14. The method as claimed in claim 11,wherein an etching rate of the protective layer pattern to H₂SO₄ and/orNH₄OH is lower than that of the mask pattern.
 15. The method as claimedin claim 11, wherein the forming of the protective layer includesforming the protective layer through an atomic layer deposition (ALD)process. 16.-19. (canceled)